This invention relates to a mechanism for separating immiscible components of a fluid mixture and, more particularly, for separating water from a diesel fuel oil/water mixture.
Although the invention disclosed in this specification can be used to separate immiscible components of any fluid mixture in which the components have different specific gravities, it is more particularly related to the problem of separating water from diesel fuel oil. Diesel engines have become increasingly popular for operating motor vehicles. Although this type of engine provides increased fuel economy over the more traditional gasoline engines, diesel engines are particularly sensitive to contaminates in the fuel oil supply, particularly water mixed with the fuel oil. It is extremely difficult to maintain fuel oil supplies such that they cannot be contaminated by water. Water mixed with fuel oil has many deleterious effects on the vehicle engine, and must be separated out for the proper operation of the diesel engine, particularly in cold weather, when ice crystals may cause the filter to plug. Furthermore, diesel fuel oil contains parafin waxes which, if the fuel oil is chilled below its "cloud point", solidify into crystals, which may plug the fuel oil filter, causing a reduction or loss of fuel flow.
Accordingly, it has become common to provide vehicles equipped with diesel engines with a fuel oil/water separator that causes the fuel oil/water mixture passing through the separator to coalesce, and thus be removed from the mixture, so that the fuel oil communicated to the engine has had its water content removed by the separator. Fuel oil/water separators used in motor vehicles are commonly of the pleated paper type or have some other coalescing and filtering media which effects separation. Accordingly, the media eventually is rendered ineffective or unusable. Therefore, most fuel oil/water separators have a replacable cartridge element which may be periodically removed and discarded and replaced with a fresh cartridge containing fresh coalescing and filtering media. Because of the design of the fuel oil/water separator, prior art fuel oil/water separators have used a cartridge which includes a sump for receiving the water separated from the mixture. Accordingly, it is also necessary with such cartridges to provide a mechanism for draining the sump periodically and it has also become customary to provide such cartridges with a probe which actuates a warning device when the water in the sump reaches a predetermined level. Accordingly, since the replacable cartridge must include the sump, a stopcock or some other means of draining the sump, and a mechanism for installing a water detecting probe, these cartridges have become relatively expensive. Such a prior art diesel fuel oil/water separator is illustrated in U.S. Pat. No. 4,292,179.